Lifting hook for annealing boxes and the like



Jan. 3, 1939. c. J. ANGSTROM ET AL.

LIFTING HOOK FOR ANNEALJNG BOXES AND THE LIKE Filed July 9, 1937 INVENTORS ATTORNEYS Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE LIFTING HOOK FOR ANNEALING BOXES AND THE LIKE Application July 9, 1937, Serial No. 152,672

6 Claims.

This invention relates to lifting hooks and more particularly to apparatus of this type which is adapted to move annealing boxes and other heavy, bulky objects.

l-Ieretofore many types of lifting hooks have been constructed for moving heavy, bulky objects and some of these hooks have been provided with link connections between the frame or the arms of the hook and the crane, or other lifting means. 10 These link connections ordinarily move or expand to substantially vertical positions when the hook is moved, and collapse to substantially horizontal positions when the hook is supported by means other than the link connections. The link connections when in their vertical positions are usually of appreciable height in relation to the load and directly add to the height of the load. Accordingly, the lifting hook has considerably greater over-all height than the load carried thereby. This is undesirable in many cases.

Lifting hooks are also made in which the load arms are free to move even when the hook is carrying a load so that a positive engagement between the load arms and the load is not secured. Then too, lifting hooks are produced in which the load arms are locked in certain positions, or their movement is limited, whenever the lifting hook is moved. Thus it is often difiicult to position the hook over a load and to engage the load arms with the load, or to disengage the load arms therefrom.

The general object of this invention is to overcome the foregoing and other difficulties of known types of lifting hooks and to provide a lifting hook that automatically locks the load arms thereof in engagement with any load carried by the lift ing hook.

Another object of this invention is to provide a lifting hook which permits movement of the hook to arms when the lifting hook is moved with no load thereon.

The above and further objects are achieved by the provision of a lifting hook having a frame from which hook arms are pivotally suspended. Levers are fulcrumed on the frame and they are adapted to hold the arms in fixed relation with any load placed thereon when the hook is moved. Springs, or other suitable means, are associated with the levers for positioning them so as to permit movement of the arms whenever the hook is not carrying a load. Other means, such as a block, is slidably carried by the frame to control the position of the levers. The block is secured to a crane-eye whereby the levers lock the hook arms in positive contact with, or in fixed relation to,

the load when the hook is raised with a load being carried thereby. The preferred embodiment of our invention is illustrated in the accompanying drawing of which Fig. 1 is a front elevation thereof Fig. 2 an end elevation thereof, the springs being omitted for the sake of clearness of the drawing; and Figs. 3 and 4 cross sections on lines IIIIII and IV--IV of Fig. 1, respectively.

Referring more particularly to the accompanying drawing, a frame I is shown as comprising two longitudinally extending side plates 2 which are held in spaced relation by a plurality of web plates 3 that are welded or otherwise secured therebetween. Arms 4 are pivotally suspended from the frame I adjacent the ends thereof and are provided with hooked or bent-over portions 5 at their ends for engaging with the load to be carried. Each arm is preferably in the form of an A-truss and includes a cross-brace E to which handles 1 are secured so as to provide ready means for grasping the arms 4. The upper (and outer) portions of the arms 4 carry outwardly directed cam plates 8 which have raised, flat surfaces 9 and beveled surfaces I 0 leading from the flat surfaces 9 to the outer surface of the arms 4.

Means are provided to prevent movement of the arms 4 when they are engaged with a load, and, in the form of the invention illustrated, these comprise levers II which are pivotally secured to the frame I at fulcrums I2 which include metal plates 3a secured between and extending below the side plates 2. The levers I I have forked ends that surround and extend beyond the arms 4 and are provided with rollers I3 which are adapted to engage with the cam plates 8. When the rollers I3 are engaged with a flat surface 9 of the cam plates the arms 4 are forced inwardly in relation to the lifting hook and are held in fixed relation with, or locked against, any load placed thereon. The levers II can move the rollers I 3 over the beveled surfaces In into a non-engaging position relative to the cam plates 8, in which position the rollers I3 do not ordinarily contact the arms 4, thereby permitting free movement thereof.

In order to position the levers II so that the rollers I3 are in non-engagement with the cam plates 8 when no load is being carried, means, such as springs I4, are associated with the levers II. The springs I4 are supported by web plates 3b and discs I5 bear upon the upper extremity of the springs. Rods I6 extend axially through the springs I4 and are connected between the levers II and the discs I5. The springs I4 have sufiicient strength to hold the levers II in the position illustrated in Fig. 1 (shown in dots and dashes) even when the lifting hook is being moved so that the arms 4 are free. Adjacent ends of the levers II are secured to a block I! which is slidably received in the central portion of the frame I for limited vertical movement. Thus the block I! is positioned by the springs l4, through the levers II, when no load is being carried, as shown in dots and dashes in Fig. l. The block I! is provided with shoulders I8 which are adapted to engage the under surface of the frame I to limit the upward movement of the block.

A crane-eye I9 is pivotally secured to the upper portion of the block I1 to provide convenient means by which the lifting hook may be moved. The crane-eye I9 is adapted to bear upon the upper surface of the frame I to limit downward movement of the block IT.

From Fig. 1 it is seen that the block I! and the springs 14 are connected to the levers I l on opposite sides of the fulcrums I 2. Thus while the springs l4 normally hold the levers ll out of operative relation with the arms 4 even though the frame is being lifted, when a load or weight is supported by the arms 4, the block I'I moves vertically until the shoulders 18 engage with the frame I. This compresses the springs I4 and moves the rollers l3 into engagement with the cam plates 8. Accordingly, the arms 4 are held in fixed relation, or positive engagement, with their load.

It is evident that the load is transferred from the arms 4 to the crane-eye l9 through the frame I. This is greatly to be desired in that the frame i can be rigidly constructed from, and braced by, suitable material so as to give maximum strength to this member.

A particular advantage of this lifting hook is that the over-all height thereof is substantially the same as the height of the load carried thereby. Thus, the lifting hook is designed to be used where there is but a small crane clearance. As the arms 4 of the lifting hook are free to move when the hook is' not carrying a load they are readily positioned to avoid striking obstacles in the path of the hook, or to engage with a load.

According to the provisions of the patent statutes, we have illustrated and described one specific embodiment of our invention. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. A lifting hook comprising a frame, arms pivotally suspended from said frame adjacent the ends thereof, a lever associated with each of said arms and carried by said frame to lock said arms in fixed relation with a load thereon when the hook is moved, means'associated with said levers for positioning them so as to permit movement of said arms when the hook is moved with no load thereon, and a member slidably received in said frame for limited vertical movement, said member being pivotally secured to said levers to control the position thereof when the hook carries a load.

2. A lifting hook comprising a frame, arms pivotally suspended from said frame adjacent the ends thereof, cam plates carried by said arms, levers pivotally secured to said frame and provided with rollers for engaging with said cam plates to limit the movement of said arms, means associated with said frame for positioning said levers with the rollers in non-engagement with said cam plates to permit free pivotal movement of said arms when the hook is moved with no load thereon, a block slidably received in the central portion of said frame for limited vertical movement, said block being pivotally secured to said levers through which said means control the position of said block when the hook is moved with no load thereon, and a crane-eye pivotally secured to the upper portion of said block.

3. A lifting hook comprising a frame, bifurcated, hooked arms pivotally suspended from said frame adjacent the ends thereof, outwardly directed cam plates carried by said arms, levers pivotally secured to and extending along the under side of said frame, said levers being provided with rollers for engaging with said cam plates to lock said arms in fixed relation with a load thereon when the hook is moved, springs carried by said frame, means connected between said levers and said springs for positioning said levers with the rollers in non-engagement with said cam plates to permit movement of said arms when the hook is moved with no load thereon, a block slidably received in the central portion of said frame for limited vertical movement, said block being pivotally secured to adjacent portions of said levers, and a crane-eye pivotally secured to the upper portion of said block.

4. A lifting hook comprising a frame, bifurcated, hooked arms pivotally suspended from said frame adjacent the ends thereof, outwardly directed cam plates carried by said arms, levers pivotally secured to and extending along the under side of said frame, said levers being provided with rollers for engaging with said cam plates to lock said arms in fixed relation with a load thereon when the hook is moved, springs associated with said frame for positioning said levers with the rollers in non-engagement with said cam plates to permit movement of said arms when the hook is moved with no load thereon, a block slidably received in the central portion of said frame and pivotally secured to adjacent portions of said levers, said block being provided with shoulders for engaging with said frame to limit the upward movement thereof, and a craneeye adapted to bear upon said frame to limit the downward movement of said block pivotally secured to the upper portion of said block.

5. A lifting hook comprising a frame, bifurcated, hooked arms pivotally suspended from said frame adjacent the ends thereof, outwardly directed cam plates carried by said arms, levers pivotally secured to and extending along the under side of said frame, said levers being provided with rollers for engaging with said cam plates to lock said arms in fixed relation with a load thereon when the hook is moved, springs carried by said frame, means connected between said levers and said springs for positioning said levers with the rollers in non-engagement with said cam plates to permit movement of said arms when the hook is moved with no load thereon, a block slidably received in the central portion of said frame and pivotally secured to adjacent portions of said levers to control the positions thereof, said springs being adapted to control the position of said block when the hook is moved with no load thereon, said block being provided with shoulders for engaging with said frame to limit the upward movement thereof, and a crane-eye adapted to bear upon said frame to limit the downward movement of said block pivotally secured to the upper portion of said block.

6. A lifting hook comprising a frame, arms pivotally suspended from said frame, a member secured to said levers for positioning them in an slidably received in said frame for limited vertical unlocking position when the hook carries no load movement, a lever associated with each of said whereby said arms are free for pivotal movearms and pivotally secured to said member, said ment on said frame.

5 levers being positioned by said member to lock CARL J. ANGSTROM.

said arms against outward movement when the ALFRED R. KRUSE. lifting hook carries a load, and means pivotally 

